As used in this application articulation means full horizontal and rotational movement until a trailer contacts a vehicle.
Prior to the disclosed embodiments of the invention, trailers using ball-style couplers did not have enough articulation when used in an off-road or construction type environment. This limits the effectiveness and usefulness of ball-style couplers. The prior art includes, U.S. Patent Application 2010/0207357 filed by Hathcock; U.S. Pat. No. 5,211,416 issued to Blacklaw; and U.S. Pat. No. 4,844,498 issued to Kerins. One difference between these prior art references and the disclosed embodiments of the invention is the lack of adaptability as a result of the omission of a size variable clamp and height-adjustable ball.
Hathcock and Blacklaw use a lunette ring coupler bracket, but do not use the size variable clamp in embodiments of the present invention. Accordingly, Hathcock and Blacklaw are more limited in that they can only accommodate one size of ball coupler. Kerins uses a latch over a trailer hitch that performs a limited version of the function of the lunette ring and, again, is limited in size. To contrast, the size variable clamp and height-adjustable ball allows embodiments of the present invention to fit a wide variety of trailer ball couplers. Hathcock and Blacklaw require modification to the ball coupler for use, but embodiments of the present invention do not. Finally, the construction of embodiments of the present invention allows full articulation in all directions as opposed to one direction only with a ball coupler. Hathcock loses articulation in the ball hook.